In my opinion this whole decision isn't directed to provide better solutions for the users but simply a monetary directed result. Before they announced this new roadmap, they had to support 3 different VS tools, VS DOTS, Bolt 1 and Bolt 2. The thing that has been already teased many times here, bolt 2 isn't anywhere near the public beta, or even 1.0 release which means it might not come to the 2020 LTS version. This could mean for the unity team, they have to support bolt 1 until 2020 LTS gets EOL, in 2022. On top of this, bolt 2 can possibly take so much time to develop, DOTS VS will actually get their own "1.0" release (which still will be a pointless toy in my opinion). There are obvious potential workarounds on this problem (like, developing bolt 2 till 2020 LTS as a package, finishing it and only then implementing it inside of the engine) but they decided not to for some reasons.